The manipulation of fluids to form fluid streams of desired configuration, discontinuous fluid streams, droplets, particles, dispersions, etc., for purposes of fluid delivery, product manufacture, analysis, and the like, is a relatively well-studied art. Droplet microfluidics are useful for a variety of purposes including high-throughput analysis of chemical and biological systems.
In many applications, several fluids must be combined in a specific sequence. Existing methods describe achieving this result by separately emulsifying a plurality of fluids as droplets, and bringing the droplets into contact at which point the droplets may be coalesced to combine the fluids. While droplet coalescence has been demonstrated for pairs of droplets, it is difficult to control.